Variable-speed transmission mechanism.



C. A. DREISBAGH. VARIABLE SPEED TRANSMISSION MEGHANISM.

APPLIUATION FILED 00T. 1l, 1911.

COLUMBIA PLANOGRAPH Co..wAsHlNG1-DN. D. c,

G. A. DREISBACH.

VARIABLE SPEED TRANSMISSION MEGHANISM.

APPLICATION FILED 00T. 11, 1911.

Patented Dec. 3, 1912.

5 SHEETB-SREET 2.

coLUMBlA PLANonRAPI-l E0..WASHINOTUN D c G. A. DREISBAGH.

VARlABLE SPEED TRANSMISSION MEOHANISM. APPLICATION HLBD 001.11, 1911.

1,646,156., Y Patented De.3,1912.

5 SHEETS-SHEET 3.

G. A. DREISBACH.

VARIABLE SPEED, TRANSMISSION MEGHANISM.

APPLICATION PLED 00T. 11, 1911.

Patented Dec. 3, 1912.

Ftp. 5,

C. A. DREISBACH.

VARIABLE SPEED TRANSMISSION MECHANISM.

APPLICATION 'FILED 0012.11, 1911.

Patented Dec.` 3, 1912.

5 SHEETS-SHEET 5.

l NTTFD? STATES! PATENTV FFTQE.

CHARLES A. DRESBACH, 0F NEW HAVEN, CONNECTICUT.

VARIABLE-SPEED TRANSMISSION MECHANISM.

Application filed October 11, 1911.

To all whom t may concern.'

Be it known that I, CHARLES A. Dems- BACH, a citizen of the UnitedStates, residing at New Haven, in the county of New Haven and State ofConnecticut, have invented a new and useful Improvement in Variable-Speed Transmission Mechanism; and I do hereby declare the following,when taken in connection with the accompanying drawings and the lettersof reference marked thereon, to be a full, clear, and exact descriptionof the same, and which said drawings constitute part of thisspecication, and represent, in-

Figure l a broken top or plan view of a variable speedtransmissionmechanism constructed in accordance with my invention, andshowing the cover removed. Fig. 2 a plan view of one end of the casing,being a continuation of the left hand end of Fig. l. Fig. 3 a similarview of the right hand of the machine, being a continuation of the righthand end of Fig. 1. Fig. 4 a side view of a portion ofthe transmissiongearing with the diiiierential casing removed. Fig. 5 is the left handend of Fig. t. Fig. 6 is the right hand end of Fig. 4f. Fig. 7 is atransverse sectional view. Fig. 8 a vertical, longitudinal sectionalview on the line L -b of Fig. 7. Fig. 9 a sectional view on the linec-CZ of Fig. 1 with the cap in place.

This invention relates to an improvement in variable speed transmission,and while especially applicable for use in automobiles or motor cycles,is equally applicable for machine tools and other work where variablespeed is required.

The object of this invention is to provide simple and convenient meanswhereby a machine may be changed from one speed to another withoutdanger of breaking the parts; and the invention consists in theconstruction hereinafter described and particularly recited in theclaims.

In carrying out my invention I employ a worm screw 2 having at one end aleft hand or reverse thread 3 which extends twice or more times aroundthe worm, and is of what T will call slow pitch. Starting from the endof this reverse thread 3, is a right hand thread which extends to theend of the worm. This thread varies in pitch so that from the point a too the thread 4 is of low pitch; from c to Z the portion 5 is of lowmedium pitch; from e to f the portion 6 is of high medium pitch; andfrom g to h the portion Specification of Letters Patent.

Patented Dec. 3, 1912.

serial No. 653,984.

7 is of the maximum or high pitch. It will be understood that t-hethread is continuous from one end of the worm to the other. The numberof the threads on the worm may be varied according to the size of themachine, and it will be understood that the reverse thread 3 may beright hand, and the thread t of left hand according to the direction inwhich the machine runs. To preserve equal centers a short eXtra thread 8is run in with the portion 5, and with the portion 6 are two eXtrathreads 9 to reverse centers, and with the portion 7 are three or moreeXtra threads 10. This worm is mounted on a driving shaft 1l having asquared portion 12 which closely lits the interior of the worm so thatmotion is imparted to it. Cooperating with the worm is a gear 13slidably mounted on a squared sleeve 14 which revolves on thedifferential or driven shaft or aXle 15 which may be the rear axle of anautomobile or shaft to be driven. This gear 13 instead of being formedwith fixed teeth, is formed with round-headed roller pins 16 equallyspaced and revolubly mounted in the periphery of the gear 13. These pinsare interlocked and bushed in any suitable manner which permits them torevolve.` These pins reduce friction and permit the ready engagement ofthe gear with the worm.

The worm is mounted in a frame 17 the ends 18 of which bear on the shaft11, and between the ends of the worm 2 and the bearings 18 areantifriction thrust blocks 19. The frame 17 has flanges 34 which restupon shoulders 35 in the casing 36. The under face of one side of theframe 17 is formed with a rack 2() which is engaged by a large gearwheel 21 loosely mounted on the sleeve 1-1 and formed integral with asmall pinion 22 which is engaged by a rack 23 operated from anyconvenient position. By moving this rack 23 the worm will be shiftedfrom one position to another so as to turn the gear in the desireddirection and at the desired speed. Tn order to hold the worm in fixedrelation to the gear at different points, the-flanges 34 on oppositesides are notched as at 24 into which spring plungers 2,5 eX- tend, andthese plungers or latches are adapted to be raised by an arm 26 on ashaft 27 which may be turned from any convenient point. In order toshift the gear to the reverse it must first be disengaged from the worm,and for this purpose the gear is formed on one side with a groove 28 inwhich a collar 29 loosely-fits, and this collar is operated by ashifting arm 30 and so that the gear may be moved to one side out of thepath of the threads on the Worm. The gear may be thrown out o-fengagement With the-Worm if desired when shifting from low to high orhigh to low.

Io reverse the motion of the machine, the Worm is unlocked and moved tothe eXtreme right which brings the reverse thread 3 over the Worm gearso as to reverse the movement of the rear axle or shaft l5. If 'Whilethe Worm frame is shifted to its high speed position and is thenunlocked and the gear 13 is not moved out of engagement With the Worm,the Worm Will at once be moved to its low speed position by means of thecontinuous thread and so that to change from high speed to low, it isonly necessary to release the Worm frame. To prevent upward thrust ofthe Worm, antifriction rollers 31 are mounted in an adjustable frame 32held in placeby the cover for the casing.

In starting the machine, the normal position is With the low speedportion of the thread on the Worm in position to engage the gear Wheel.Then if the Worm is moved to the left the increase in pitch and theeXtra threads Will increase the movement of the gear, and hence increasethe movementof the machine; but before moving the Worm the springplungers 25 must be raised so as to release the Worm frame from thecasing. The gear Wheel is then moved to one side Which may be done by afoot pedal, and then intermediate point. When stopped the springplungers are dropped to lock the Worm in position and the gear Wheelmoved 'back into engagement With the Worm if it has been moved. In thecase of an automobile, the driven portion of the rear axle is connectedWith the other portion through a differential gearingv as shovvn in Fig.7, but Which forms no part of thisinvention and which does not needfurther description other than to say that it is driven by t-he sleeve14- to Which it is rigidly connected.

I claim l. In a variable speed transmission mechanism, the combinationwith a gear and` Worm, said gear carrying in its periphery roller pinsadapted to be engaged by the said Worm, and means for shifting saidWorm.

2. In a variable speed transmission mechanism, the combination With agear and Worm, said gear carrying in its periphery roller pins adaptedto be engaged by the said Worm, means for shifting said Worm, and meansfor *moving the gear out of engagement With said Worm.

3. A variable speed transmission mechanism comprising a Worm and a gear,a frame in Which the Worm is mounted, meansv for shifting the frame andWorm, means for locking the frame at its various points of adjustment,and means for moving the gear into and out of engagement With said Worm.

In testimony whereof, I have signed this specification in the presenceof tWo subscribing Witnesses.

CHARLES A. DREISBACH.

Witnesses Y Y FREDERIC C. EARLE, CLARA Ii. WEED.

Copies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patenti- Washington. D. C.

